The invention relates generally to recoilless projectile launchers, and more particularly to a recoilless projectile launcher system using three tubes and a dispersible countermass.
Recoilless launchers are generally categorized based on their system of propulsion. In rocket motor-based propulsion systems, the motors hot toxic gases, smoke and sound are directed out the rear of the launch tube. For obvious safety reasons, this prohibits this type of recoilless launcher from being used in enclosed spaces. In powder charge-based propulsion systems, a countermass mounted in the launch tube is pushed out the rear thereof as the projectile is pushed out the forward end thereof. The countermass is generally designed to disperse harmlessly upon exiting the launch tube. The propulsion gases may or may not be vented, but are generally lesser in quantity when compared with rocket motor-based propulsion systems. Examples of countermass systems for use in powder charge-based propulsion systems are disclosed in U.S. Pat. Nos. 4,759,430 and 5,952,601.
In each of the above-noted patented systems, a piston pushes on a dispersible countermass as the powder charge burns. More specifically, in U.S. Pat. No. 4,759,430, an iron powder countermass is maintained in a cartridge attached to the piston. The piston and cartridge are propelled towards the launchers breech end where the piston is arrested and the iron powder flies from the cartridge. In U.S. Pat. No. 5,952,601, a liquid countermass is maintained in a pressure vessel designed to fly with the launched projectile. A piston mounted in the pressure vessel applies pressure to the liquid countermass causing it to exit the launch tube. However, both systems use the countermasses that generate radial or side loading since they are dimensionally unstable substances, i.e., they are only held in place by a container. The side loading forces can be transferred to the launch tube and, ultimately, to the launch personnel thereby effecting the launch and possibly injuring the launch personnel.
Accordingly, it is an object of the present invention to provide a recoilless projectile launcher system.
Another object of the present invention to provide a recoilless projectile launcher system for use in powder charge-based propulsion launchers.
Still another object of the present invention to provide a counter mass-based recoilless projectile launcher system that eliminates side loading as the countermass is propelled from the launch tube.
Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
In accordance with the present invention, a recoilless projectile launcher system has a launch tube open at muzzle and breech ends thereof. A projectile residing in the launch tube has a forward end pointing towards the launch tube""s muzzle end and having an aft end pointing towards the launch tube""s breech end. A propellant charge is coupled to the aft end of the projectile. A first tube is slidingly fitted in the launch tube, is coupled to the aft end of the projectile, and encases the propellant charge. The first tube has a first portion extending from the propellant charge towards the launch tube""s breech end and has a second portion extending from the first portion towards the breech end. The first portion has a constant inside diameter while the second portion has a reduced inside diameter relative to the constant inside diameter of the first portion. A piston, slidingly fitted in the first portion of the first tube, is positioned adjacent the propellant charge. A second tube is coupled to the piston and extends towards the launch tube""s breech end. The second tube has a constant inside diameter and a constant outside diameter with the constant outside diameter forming a sliding fit with the second portion of the first tube. A dispersible countermass resides in the second tube and is dimensionally stable independent of the second tube.